Stress or pressure sensors are commonly manufactured by providing one or more piezoresistive elements on or in a diaphram. When the diaphram is flexed, a stress is placed on those piezoresistive devices, causing a change in resistance thereof. The resistance of such an element, at any given time, will therefore provide an indication of the pressure on the sensor at that time.
A problem with such a system relates to the fact that the resistance of such a piezoresistive device, and the sensitivity to changes in the stress, both are dependent upon temperature. In order to compensate for such sensitivity to temperature, prior art systems have provided complicated electronic circuits, containing many active elements, in order either to adjust the input voltage to the sensor element or to compensate the output signal directly so that the output signals will be dependent upon stress or pressure only.
A system which used only passive elements, such as resistors, to provide such compensation would be desirable for several reasons. Such a system could be more simply, and more inexpensively, fabricated. Furthermore, such a compensation system could be more easily fabricated as part of a single monolithic integrated circuit containing both the compensation system and the sensor element. This helps to improve sensor accuracy by reducing errors due to thermal gradients within the sensor housing.